I think that could be one of the hardest, yet most necessary parts of our faith. The ability to put "all" of our faith in God no matter what. It is hard to come to the place in our walk with the Lord that we say, "I will do what's right and trust God to take care of things, but even if He doesn't take care of things I will still do what is right." What if God does not heal us like we thought he would? What if God doesn't keep our house from being foreclosed upon? What if we lose our job? What if our kid turns out to be a drug addict? Will we still say "blessed be the name of the Lord?" Will we still walk with God and put all of our faith in Him? Or will we start to look for other answers and other solutions.
I think that the 3 Hebrew teenagers had already made some hard decisions before they ever were faced with this life and death decision. The reason they had the strength to pass this test is because they had passed all of the smaller ones along the way. They refused to eat the kings food that went against their Jewish diet. They refused to live life the way the others around them were living. These tests prepared them for the day that a king would order them to be thrown into a fiery furnace.
I always find it a little difficult to hear people say they will give their life before they will ever deny Christ. They think that if the choice had to be made between denying Christ and living, or confessing Christ and dying, they would be able to choose death. Yet when you look at the small everyday 'tests' that are placed in front of them, they fail every time. When it comes between serving their neighbor or doing something for themselves, they always choose their own interest. When it comes between giving or receiving, they always choose the latter. When it comes between sharing their faith and being ridiculed at work, or keeping their mouth shut and being promoted, they will take the promotion every time.
It is very rare that the choice will come to us to be 'all in' or die. But we do face small choices every day that will prepare us in case that time ever comes. So whatever your test is today, go all in.